Testing Viscous Coupler with Automatic Transmission
MrWhoopee
Wagonist
Testing the viscous coupler with a standard transmission consists of raising all 4 wheels off the ground, then starting the engine, putting the car in gear, letting the clutch out with the engine idling and setting the e-brake. If the engine dies, the VC is good, if it slows but then recovers, the VC is bad.
With an AT, the engine won't die with the drive-train locked up. So, how does one test the VC with an AT?
After giving this some thought, I THINK I may have the answer. Performing the same test with an AT should cause the front wheels to stop rotating along with the rear if the VC is good. The engine will do exactly the same thing it does when you use the brakes to stop the car while in drive.
Has anybody performed the VC test with an auto? What were the results?
With an AT, the engine won't die with the drive-train locked up. So, how does one test the VC with an AT?
After giving this some thought, I THINK I may have the answer. Performing the same test with an AT should cause the front wheels to stop rotating along with the rear if the VC is good. The engine will do exactly the same thing it does when you use the brakes to stop the car while in drive.
Has anybody performed the VC test with an auto? What were the results?
Comments
I didn't try any e-brake tests. I can do that this weekend though.
Yes, when one wheel spins free, no power transmits to the other. It is when both wheels have grip that things start to move.
This thread doesn't suggest a different test for AT and the info is taken from FSM. Perhaps we just confirm this by looking at the FSM again.
About the AT and setting the parking brake, it might not take much torque to overcome the torque converter. I would set the parking brake and see if all wheels stop and if they do I would give it a little throttle to load the VC harder. Should give you some idea of how tight the VC is.